Astroblog

Obscured by Clouds. The rough and ready blog of a cloud benighted biologist and amateur astronomer. Astroblog will cover my interests in astronomy, biology and Life, the Universe and Everything.

Friday, April 30, 2010

Let the Moon be Your Guide

So I gave a talk at the Bellevue Heights Junior Field Naturalists Club. I was giving a talk to a group of 6-9 year olds and their parents on astronomy on a night when the sky was so cloudy no hint of the full Moon. For Field Naturalists you would want to get them out in the field doing things: looking at the stars, finding south, measuring the Moon for the Moon illusion and that sort of thing.

But with the the sky clouded out, how was i going to keep 30 or so active youngsters entertained for 45 minutes or so?

I had a theme "Let the Moon be Your Guide" and the main aim was to a) use something big and obvious to help find interesting objects and b) show that you don't need fancy equipment to see interesting in the skies. So I made some scripts in Celestia and Stellarium showing the Moon near interesting objects.

I also had some pictures of the Moon, a a big soccer ball (the Earth), a small soccer ball (the Moon), and a very big torch (the Sun) to demonstrate Moon phases. The kids were fantastic, they were enthusiastic and not afraid to talk about things. I had enthusiastic assistants to hold the Sun, Moon and Earth and demonstrate orbits and phases. I put up a picture of the Moon and had them find the Man, Lady and Rabbit (the also saw Crabs and Snails, and heck, they were right). I handed out star maps (but forgot to explain how to use them - blast!). The kids seemed to enjoy themselves, I certainly did (Thanks Rona for inviting me! and the kids for their infectious enthusiam).

As you know I'm a fan of using the freeware programs Celestia and Stellarium. I've put up the scripts for you to download and play with; download Moons.cel and put it in your Celestia folder, then use File | Open Script to run it. Download The Moon Guide and put it in scripts folder (unfortunately, it's version 0.9 script, I'll translate it to 1.03 later).

Carnival of Space #151 is here.

Carnival of Space #151 is now up at Weird Sciences. The theme of this carnival is "The Future Energy Debate". As well as energy debates there's the return of Hayabusa, bubbles as models, more 2012 debunking, direct imaging of exoplanets, the great CMB cold spot and much, much more. Fire up the Prius and drive on over.

Thursday, April 29, 2010

Mobile Phone Venus

In line with the mobile phone Moon images, here's some images of Venus taken with my mobile phone. The biggest issue is keeping the blasted phone still (and yes, I have no idea why the last image is rotated in blogger).

Tuesday, April 27, 2010

Mobile Phone Moon

Left image, Clouded Moon photographed by my mobile phone through 10x50 binoculars. Right image, Moon photographed with my mobile phone using red cellophane as a filter.

AS always, I'm looking for ways to do low cost astrophotography, and the combination of binoculars and mobile phone cameras is pretty low cost, but does come with one surprisig disadvantage, not usually a feature of astrophotography.

The images of the Moon are too bright.

I've tried several way to filter the Moons light, conistent with the "low cost" approach. Clouds work reasonably well, but are quite impractical, red cellophane distorts the image too much. The flat, dark 3D glasses thay give out at cinemas aren't dark enough, neither are my polaroid glasses. Overexposed film might work, but no one has large 10x50 sized chunks of overexposed film about these days.

Monday, April 26, 2010

The Sky This Week - Thursday April 29 to Thursday May 6

The Last Quarter Moon is Thursday May 6. Venus is readily visible in the twilight near the bright star Aldebaran. Mars is close to the Beehive Cluster. Saturn is seen in the evening above the northern horizon near the bright stars Regulus and Spica. Jupiter is easily seen in the morning sky. On Friday April 30 the Moon is very close to the bright star Antares in Scorpius.

The evening sky facing west in Australia on April 30 at 6:15 pm local time showing Venus, the V-shaped Hyades cluster and Aldebaran.

The Last Quarter Moon is Thursday May 6.

Saturn is rising before Sunset and is easily visible in the evening sky as the bright yellow object between the bright stars Regulus and Spica. Now is still a very good time for telescopic observation of the ringed world. On the 1st of May, Saturns' Moon Titan cruises just below the planets south pole.

However, it is best to wait until around 10 pm, when Saturn is quite high in the sky for the best telescopic views. Saturn's' rings are opening, and look quite beautiful, even in a small telescope. If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums.

On Friday April 30 the Moon is very close to the bright star Antares in Scorpius.

Bright white Venus continues to rise above from the twilight glow. Venus is now readily visible above the western horizon half an hour after Sunset, and even before. From Thursday 29 April to Sunday 2 May , Venus is close to the Hyades cluster and the red star Aldebaran. You will need a flat, level horizon to see them at their best low in the late twilight sky.

Jupiter is now easy to see in the morning sky as the brightest object above the north-eastern horizon.

Evening sky looking North showing Mars, Saturn and bright stars at 9:15 pm local time on Sunday May 2. Click to embiggen.

In the evening Mars can be seen low in the north-western sky as the brightest (and clearly red) object in that part of the sky. Red Mars is in the constellation of Cancer, near the Beehive Cluster (Praesaepe).

Mars is moving rapidly, leaving behind the beautiful Beehive Cluster.

Mars forms a line with the bright stars Sirius and Procyon. Mars forms another line with Regulus, Saturn and Spica.

Unexpected Rainbows (Part 14)

This rainbow at SmallestOnes' friends birthday party took us by surprise. You really need to click on it and enlarge to see all the details.

Not only is there a very bright primary bow, and a dimmer secondary bow above, just underneath the primary bow (best seen at far right) is a whole range of extra fringes that you would not normally see.

Sunday, April 25, 2010

Carnival of Space #150 is here.

Carnival of Space #150 is now up at at the Next Big Future. Yeah, this is a little late but I didn't get the usual warning email. The New Mars Space vision dominates this issue, along with asteroids, life on Titan (maybe), nuclear power debates, brown dwarf, self replicating space probes and much, much more. Construct yourself a space craft and head on over.

ANZAC Day, April 25, 2010

This is the 95th Anniversary of the dawn landing at ANZAC cove, Gallipoli. Mum (WRANS, signals, HMAS Cuttable) can't march again this year, but hopes to make it next year. I went to the service at Semaphore. It's hard for non-Australians to grasp why we commemorate a complete and utter disaster, but that's us as a nation. To re-enforce this, strange to overseas sensibilities, the march to the memorial was started by playing a song about a larcenous vagabond who commits suicide.

Appropriately, this year Jupiter accompanied us. The overlord of the planets played host to the State Member for the area, the Federal member for the area and the Mayor of Port Adelaide-Enfield. Why such a pooling of political power at humble Semaphore, rather than the Port itself? Maybe because the port hosts the Flotilla of Light?

Every year the crowd seems to get bigger, but thye don't really participate in either the hymns or the National Anthem, perfering to let the invited singer do all the heavy lifting. It's another mark of us as a nation that no-one knows more than the first two lines of our National Anthem.

The Last Post plays, children cry as the honour regiment fires a tribute, and we disperse into the paling dawn.

Saturday, April 24, 2010

Using The Gimp for Astrophotography (Part 1)

Left image: Single shot using a Canon IXUS, with an 8 second exposure at ISO 400. Right image: Composite image of 5 stacked images taken under the same conditions as image one, stacked in The Gimp (click to embiggen).

Last Sunday on Weekends with Ashley Walsh, in the computer show they were discussing programs for digital photography, and someone rang up about astrophotography. This spurred me to complete an article that I've been writing forever about using the Gimp for astrophotography. This is the first installment, based on the query to the computer program. Even simple "point and shoot" digital cameras can get good results.

With the advent of affordable digital cameras, webcams and even mobile phone cameras, amateur astrophotography has exploded. Most digital astronomy images need some degree of post processing to bring out their best, and programs such as Photoshop and PaintShop Pro have been pressed into service with remarkable results. However, the open source movement has produced some equally remarkable, and above all free, software, and one of these is The Gimp.

While The Gimp isn’t Adobe Photoshop, it’s pretty close in many respects, and can do almost anything an amateur wants to do. And as a free program, you can’t beat the price. Astrophotography post processing can be broadly divided into a small number of themes. Stacking and adjusting stacked images, stitching images together to make a larger image (such as constructing a full lunar image from smaller segments) and making animations. The Gimp is very useful for all of these, although for automatic stacking and registration of hundreds of images from CCD cameras you are better off with a dedicated program like Registax.

Left image, two shots overlaid using the "difference" function of the Gimp. Right Image: Image in difference mode when images have been aligned.

I’ll start off with the simplest task, preparing a single image using a digital camera in The Gimp. You may be surprised to learn that ordinary, cheap, "point and shoot" digital cameras are perfectly capable of taking decent sky shots. Simple ones, like my Olympus mu 300 don’t have the ability to take timed exposure's but most of these cameras have a nightmode that will allow you to take up to 6 second exposures. This is more than adequate for taking images of the Moon, conjunctions of bright planets,and so on. More advanced digital cameras like my Canon IXUS can do timed exposures (the Canon can do up to 15 seconds). If you do have a camera with a timer function, don't go over 10 seconds exposure or the stars will start trailing.

So the first thing you need to do is take some photos. You need a camera of course, and a tripod of some sort to keep the camera steady. I have both a standard camera tripod, and one of those little portable tripods for use hiking etc. The images in this post were taken on one of those little portable tripods. These images were taken simply by pointing the camera at the sky and taking a shot, no binoculars or telescopes involved, and yes, that's the Pleiades cluster at decent magnification taken with a simple point and shoot camera (I'll discuss telescope/binocular imaging in future posts).

For stacking I take up to 6-8 images, depending on the circumstances. Quite often only 4 images will suffice, but extras are good in case of misfires, or if I want to make an animation. If your camera shows "hot" pixels, pixels which are permanently on (you'll see them as bright, single pixels where stars aren't on your images), then you need to take a dark frame, this is an image that is identical to the other exposures, but with the camera lens covered.

Once you have your images, and transferred them to hard disk or whatever storage medium you want, open The Gimp. Make sure the "layers, channels paths" panel is open It's normally opened by default, if not File | Dialogs | Create New Dock | Layers, Channels, Paths will open it.

The open the first of you sequence of images. You will note it appears in Layers window as a thumbnail labeled "background". If you have "hot pixels" , use the dialogFile | Open as layers. This image then appears as a highlighted thumbnail in the Layers window. In the Mode dropdown box in the layers menu, choose "subtract". The save the resulting image with a new file name. Repeat this for each image you want to stack (you can create scripts to do this, but we will cover this later).

Once you have all your images processed for hot pixels (or if your images don't have enough hot pixels to worry about), open the first image in the sequence you want to stack as before (the processed ones if you have hot pixels). Again note that it is labeled "background), again do the File | Open as layers to get the next image in the sequence. This time, in the Mode drop down you choose "difference" (see left image above, you will have to enlarge it to see the detail). Both images now appear overlaid. Why are they not on top already? Because in the 6-6 seconds you took obtaining that image, Earths rotation has moved the stars sufficiently so they are no longer in the same spot. For best overlay results, you may wish to enlarge the images using View | Zoom.

Choose the move icon in the main Gimp panel, then click on the image and use the arrow keys to move the images around until they are on top of each other. With the "difference" mode, you know this occurs when the images disappear (see right hand panel above). Now change the mode to "addition" and instantly the stars are brighter.

Open your next image in the sequence using File | Open as layers and repeat as before. Continue with all your images or until the stars are sufficiently bright. You will notice that while some stars are prefectly aligned, stas far from those you aligned trail a bit. That is because the sky is a sphere, and the stars are rotating as they move. You can fix this using the rotation tool, but that's a bit painful, just live with a bit of trailing for now until you have some experience stacking the images.

Now you have you assembled image, save it in the format you want and Robert is your avuncular relative, an nice sky shot, almost as good as with expensive cameras! (go back and check the top right hand image)

Sadly, my experience was not optimal. As MiddleOne got a flight simulator program for his birthday, he's rigged up headphones to the computer for it. Headphones with a cord that reach his ears but not mine. So I now have tiny headphones on the desk, trying to listen to Gianluca narrate what's going on. Can't hear much. Anyway, here's some images from the session to enjoy.

Wednesday, April 21, 2010

The Case of the Missing Comet (or - where oh where is Catalina)

Left image, predicted position of comet C/2009 O2 Catalina as seen from the STEREO Behind spacecraft on 13 April at 8:49 UT as visualised in Celestia. Right image, an actual image of the same area from the STEREO spacecraft on 13 April at 8:49 UT. Comparison stars (Algedi, Dabih) are indicated in both images, click to embiggen.

For the past few days the stereohunters have been watching the images from the H1 instrument of the STEREO Behind sapcecraft, comet C/2009 O2 Catalina, already faintly visible in H1A images, was going to come within about 0.23au of STEREO B. Orbital predictions (see above left image, from orbits entered into Celestia) suggested the comet would cross the H1B imaging area on April 13 (CometAl's predictions put it further left than mine, to the left of Algedhi, but still within the image frame).

Well, as you can see in the righthand image, which is spectacularly devoid of any comet, this did not come to pass. I checked all the 13th and most of the14th, and nothing appeared. The Stereohunter list was silent. Obviously the comet didn't appear. It was still visible in the H1A camera, faintly, so it hadn't evaporated. What happened?

It simply looks like the earlier orbital elements were out, here is the position of C/2009 O2 Catalina seen from H1B as plotted in SkyMap using the latest orbital elements from JPL HORIZONS (as before the comaprison stars Algedi, Dabih are shown, the black rectangle is the edge of the H1B image frame).

Tuesday, April 20, 2010

The Sky This Week - Thursday April 22 to Thursday April 29

The Full Moon is Wednesday April 28. Venus appears low in the twilight and is near the beautiful Pleiades cluster. Mars is close to the Beehive Cluster. Saturn is seen in the evening above the north-eastern horizon near the bight stars Regulus and Spica and is close to the Moon on Sunday April 25. Jupiter is easily seen in the morning sky.

The evening sky facing west in Australia on April 25 at 6:10 pm local time showing Venus and the Pleiades cluster.

The Full Moon is Wednesday April 28.

Saturn is rising around before Sunset and is easily visible in the evening sky as the bright yellow object between the bright stars Regulus and Spica. Now is still a very good time for telescopic observation of the ringed world. On the 23rd, Saturns' Moon Titan cruises just above the planets north pole.

On Sunday 25 April the Moon is close to Saturn, then on Tuesday the nearly full Moon is very close to the bright star Spica.

However, it is best to wait until around 11 pm, when Saturn is quite high in the sky for the best telescopic views. Saturn's' rings are opening, and look quite beautiful, even in a small telescope. If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Bright white Venus continues to rise above from the twilight glow. People with flat, level horizons can see Venus above the western horizon half an hour after Sunset. From Thursday 22nd April to Sunday 25 April , Venus is close to the Pleidades cluster. You may need binoculars to see the faint cluser close to the horizon and you will need a flat, level horizon to see them low in the late twilight sky.

Jupiter is now relatively easy to see in the morning sky as the brightest object above the eastern horizon.

Evening sky looking North showing Mars, the Beehive Cluster and the Moon at 9:30 pm local time on Thursday April 22. Click to embiggen.

In the evening Mars can be seen low in the north-western sky as the brightest (and clearly red) object in that part of the sky. Red Mars is in the constellation of Cancer, near the Beehive Cluster (Praesaepe).

Mars is within binocular range of the beautiful Beehive Cluster this week. While Mars and the Beehive are easily seen under dark country skies, in the suburbs you will need binoculars to to see them. Even in low power binoculars they will look great.

On Thursday 22 April the waxing Moon is close to Mars, then on the 26th the waxing moon is close to the bright star Regulus.

Mars near the Beehive cluster, simulated 10x50 binocular view.

Mars forms a line with the bright stars Sirius and Procyon. Mars forms another line with Regulus, Saturn and Spica.

Airfix in the House (Part Two)

MiddleOne has now completed his first Airfix model. You may remember it started off like this, back on his natal day. After much painting, and fiddly transfere sticking, it' together. Okay, so the paint scheme is wrong (but the instructions had incorrect labels in some cases) and the front fins are backwards, but Middle One did it almost all himself with little input from me.

Saturday, April 17, 2010

Wait! Mercury Has a Tail (and an astreoid occultation)

A few days ago I posted some images of Mercury with a tail as seen in the STEREO spacecraft H1b imager. But I realised that the image of the Mercury tail in the H1a imager I referred too was pretty rubbish. So I've now posted one of my more recent images. The image on the right is Mercury as seen in the H1a imager on January 16 of 2010.

For contrast I've put the image from the H1b imager of 8 April on the right. The tail in the H1a imager is better on the 17th, but I've shown the 16th because of a rather unusual circumstance. On the 16th an asteroid passes behind Mercury, so you get a tail and an asteroidal occultation in the same picture. The tail (it points to the left in the lefthand image, and right in the righthand image, the vertical bar is an imager artefact) is easier to see in the animations (see below) which show the asteroid shooting behind Mercury. I haven't identified the asteroid yet, the horizons ephemeris for Mercury from H1a seems off, but I'll sort it out eventually. Update: The asteroid is 88 Thisbe.

As I noted in the last article, we are pretty convinced the tail we're seeing is the sodium tail of Mercury, where the solar wind blasts sodium ions off Mercury's surface. From the STEREO imagers, you can only see the tail when Mercury is at inferior conjunction, when most of Mercury's surface is dark, and it's light doesn't overwhelm the image. However, inferior conjunction as seen from Earth is not the same for the STEREO ahead and behind craft. Mercury was at inferior conjunction on 5 January, but it was not until 16-17 January the Mercury was close to that position as seen from STEREO ahead. Similarly, inferior conjunction is not due to be seen from Earth until April 29, but was seen at this position on the 8th from the STEREO behind space craft. Of course, being stupid I didn't realise this apsect of the geometry, and my surveys to find the tail in H1b failed. Once Jiangao Ruan spotted the H1b tail, I finally realise what had been wrong.

Mercury as seen from STEREO A (ahead) on January 16 and STEREO B (behind) on April 8.

As well as the right geometry from the point of view of the spacecraft being needed to see the tail, the tail is most intense when Mercury is at Perihelion (ie closest to the Sun), Mercury was about a month from aphelion on the 16th of January, and was 8 days past Perihelion on the 8th of April. You can see the tail is more distinct in the image from the 8th than the 16th. The stereoimagers let only 5% of the sodium spectrum through, which is enough to see the tails, but not enough for them to be prominent.

You can download an avi of Mercury showing the tail on 16 January 2010 with the astreiod shooting behind Mercury (caution 2.4 Mb) here and a smaller version (0.2 Mb) here. Or you can play the YouTube video below, it's a bit jerky and hard to see the asteroid though.

Friday, April 16, 2010

Venus, Moon and an Occultation of the Pleiades April 17, 6:00-7:00 pm

The evening sky facing west in Australia on April 17 at 6:25 pm local time showing Venus and the crescent Moon. The Moon occults some of the Pleiades cluster at this time from parts of Australia.

On Saturday 17th April, the crescent Moon is close to Venus and for many folks in Australlia and New Zealand there is an occultation of the Pleiades, The link shows the local times of the occultation.

You will need a flat, unobscured horizon to see the occulation. You will probably need binoculars or a small telescope to see the Pleiades as the sky will be relatively bright and the stars will be dim.

In contrast, both Venus and the Moon are bright enough to see in the sky in the early twilight. Low, but high enough above the horizon that you should see them unless it's fairly hilly.

Even if you miss the occultation, or its not visible from your location. You will still see the crescent Moon close to the pretty cluster. Again, you may need binoculars to see the faint cluster close to the horizon.

Woo Hoo!! Simon Singh Wins!

Simon Singh, scientist and science writer, who was being sued by the British Chiropractic Association for the temerity of writing the truth, has had the libel case against him dropped. While this is a win and cause for celebration, there's a long way still to go. As Simon writes:

“It still staggers me that the British Chiropractic Association and half the chiropractors in the UK were making unsubstantiated claims. It still baffles me that the BCA then dared to sue me for libel and put me through two years of hell before I was vindicated. And it still makes me angry that our libel laws not only tolerate but also encourage such ludicrous libel suits. English libel law is so intimidating, so expensive, so hostile to serious journalists that it has a chilling effect on all areas of debate, silencing scientists, journalists, bloggers, human rights activists and everyone else who dares to tackle serious matters of public interest. In the area of medicine alone, fear of libel means that good research is not always published because those with vested interests might sue, and bad research that should be withdrawn is not pulled because the authors might sue the journal, and in both cases it is the public that loses out because the truth is never exposed. My victory does not mean that our libel laws are okay, because I won despite the libel laws - we still have the most notoriously anti-free speech libel laws in the free world.”

Thursday, April 15, 2010

Carnival of Space #149 is here.

Carnival of Space #149 is now up at Starry Critters, there's Klingons at the Space Station, a mini-Moon carnival, a Messier Marathon, Venus and Mercury and much, much more. Buzz on over and have a look.

Wednesday, April 14, 2010

Mercury in STEREO H1b

This is Mercury as seen in the STEREO spacecraft H1b imager (8-4-2010 left, 9-4-2010 right), if you think it looks vaguely cometary, you are right. Mercury has a tail. Now the question is, is the tail real, or an imaging artefact. Now Comet Al, myself and a few others have been following these apparent tails in the H1a imager. (the first time I saw it, I thought it was a comet).

We are pretty convinced we're seeing the sodium tail of Mercury, where the solar wind blasts sodium ions off Mercury's surface. However, proving this is hard. You can only see the tail when Mercury is at inferior conjunction (Ie when most of Mercury's surface is dark, and it's light doesn't overwhelm the image), and the orientation of the tail changes as Mercury approaches the Sun, and you can see it im multiple conjunctions over the years. Seeing the tails in the H1b imager, in the correct orientation, makes it even less likely that this is an artefact (first spotted by Jiangao Ruan, congratulations we've been searching for this for a while).

You can download an avi of Mercury showing the tail on 8 April 2010 (caution 1.6 Mb) here.

Animated Mercury with tail in YouTube, unfortunately, compared to the avi, it doesn't work very well.

The Sky This Week - Thursday April 15 to Thursday April 22

The First Quarter Moon is Wednesday April 21. Venus appears low in the twilight and is near the crescent Moon on Saturday April 17. The Moon covers the beautiful Pleiades cluster at this time. Mars is close to the Beehive Cluster. Saturn is seen in the evening above the north-eastern horizon near the bight stars Regulus and Spica. Jupiter is easily seen in the morning sky.

The evening sky facing west in Australia on April 17 at 6:25 pm local time showing Venus and the crescent Moon. The Moon occults some of the Pleiades cluster at this time.

The First Quarter Moon is Wednesday April 21.

Saturn is rising around before Sunset and is easily visible in the evening sky as the bright yellow object between the bright stars Regulus and Spica. Now is still a very good time for telescopic observation of the ringed world. On the 15th, Saturns' Moon Titan cruises just under the planets south pole.

However, it is best to wait until around 11 pm, when Saturn is quite high in the sky for the best telescopic views. Saturn's' rings are opening, and look quite beautiful, even in a small telescope. If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Bright white Venus continues to rise above from the twilight glow. People with flat, level horizons can see Venus above the western horizon half an hour after Sunset. On Saturday 17th April, the crescent Moon is close to Venus and for many folks there is an occultation of the Pleiades, (see the link for local times of the occultation). Even if you miss the occultation, you will still see the crescent Moon close to the pretty cluster, although you may need binoculars to see the faint cluser close to the horizon (and again, you will need a flat, level horizon to see the event).

Jupiter is now relatively easy to see in the morning sky as the brightest object above the eastern horizon.

Evening sky looking North showing Mars, the Beehive Cluster and the Moon at 9:30 pm local time on Thursday April 22. Click to embiggen.

In the evening Mars can be seen low in the north-western sky as the brightest (and clearly red) object in that part of the sky. Red Mars is in the constellation of Cancer, near the Beehive Cluster (Praesaepe).

Mars comes within a finger width of the beautiful Beehive Cluster between 15 and 18 April. While Mars and the Beehive are easily seen under dark country skies, in the suburbs you will need binoculars to to see them. Even in low power binoculars they will look great. Although Mars is closest early this week, it still remains in binocular range for the rest of the week.

Mars near the Beehive cluster, simulated 10x50 binocular view.

Mars forms a line with the bright stars Sirius and Procyon. Mars forms another line with Regulus, Saturn and Spica. Mars is also close to the Moon on Thursday 22 April.

Sunday, April 11, 2010

Public Lecture in Melbourne - Cosmic Dark Ages

The Australian Science Communicators have a free public lecture on Friday 16 April 6:30 pm at the Swinburne University (Melbourne, Victoria). It's about the Cosmic Dark AGes, those early moments of the Universe before it became transparent to light. Details are here. You will need to RSVP.

Gondwana was the Earth's last great "supercontinent" - a vast tectonic amalgamation that included Australia, Antarctica and India juxtaposed in East Gondwana around 500 million years ago.

Although East Gondwana's amalgamations have been broadly understood for some time, the dense Antarctic ice cap has kept many details well hidden. Research at the University of Adelaide, however, appears to be changing that.

Using the remote-sensing technique magnetotellurics, the team recently "looked through" the ice to image a massive proposed suture zone extending deep into the Earth's crust.

In this fascinating presentation, ARC Post-Doctoral Fellow Dr Kate Selway reveals their findings and explores ways in which they've enhanced understanding of the geological history of our planet.

April marks the 50th anniversary of SETI, or the search for extraterrestrial intelligence. So what do we know today? Is there life in the cosmos, waiting to be found? Or is Earth the only harbour of life as we know it? And if life exists elsewhere, what about intelligence, technology and civilisation? Science journalist Wilson da Silva updates the Drake Equation, science's attempt to determine the number of extraterrestrial civilisations out there today.

Also, from April 9 the RiAus is opening up the bar at the Science Exchange, Friday afternoons from 5pm, so if you're looking for somewhere a little bit different to relax and unwind after work, drop on by.

Friday, April 09, 2010

Control the Virtual Telescope Yourself!

During Global Astronomy Month, the folks at the Virtual Telescope as letting people control it themselves, day or night, until April 30th. Naturally, as a freebie there will be a lot of interest, so they are restricting people to 30 minutes time on the scope, and between 5 -10 users from any given country a night (so everyone gets a go). No previous astronomical experience is necessary.

Educators, this would be a great chance to get your students exposed to astronomy in a way they will be unlikely to experience easily (Australian Educators have the best opportunity, our daytime is early morning at the scope, when most Europeans will be in bed).

I've applied for time to see a rare alignment of Saturn's satellites. If this works out I can set up something for my kids primary school hopefully).

My First Astrophotos

The Southern Cross (back to front). The flares are damage to the negative.

On the Easter long weekend we cleared out the office and converted it to a bedroom for EldestOne. This involved a lot of carting of heavy objects, bookshelves, sofas, bookshelves, beds, multiple desks, more bookshelves and so on.

Of course, all this uncovered all sorts of treasure troves, books that we hadn't read for ages, or had forgotten existed, and a whole pile of ancient photos. Amongst the embarrassing and out of focus photographs of me at scout camp, or going off to high school was an undistinguished packet of negatives. My first astrophotos.No idea what stars these are really, possibly part of Carina.

Actually, they are probably not my first astrophotos. But the first astrophotos that actually had something on the negative. Amongst my arsenal of cameras was an old box brownie (old even back in the 60's). Being an astronomy nut way back then, I tried taking pictures of the sky with the box brownie as I could hold open the shutter manually, but I couldn't keep it steady for long enough. So I ended up with a lot of blank negatives.

Then in the early 70's my friends gave me an even older camera, one with a bellows like arrangement for adjusting image size, as a joke.

But it worked, the shutter release could be snicked down and left, and the box had an attachment for a stand, so I could mount it (somewhat awkwardly given the camera mount wasn't meant for "modern" stands, gaffer tape was involved) so I didn't have to hold the camera. And you could still get film for it without paying n arm and a leg.

In the packet there are negatives of a few star trails of varying length, and a whole series of (mostly out of focus) photographs of a partial solar eclipse, taken using the projection method with my 50 mm refractor. From a couple of non-astronomical photos and the eclipses visible from Brisbane these where probably taken either in 1972 or 1973 when I was 16 or 17.

So for 37 years I've been trying out low cost astrophotography. Of course in those days the local film developers had no idea about printing astronomical shots, and I had no resources to do it myself, so they just developed the negatives and left it at that.

But here I've scanned the original negatives, inverted them with The Gimp (hey, it was the 70's and they were B&W pictures in the first place) and done only minor contrast adjustments.

Thursday, April 08, 2010

Carnival of Space #148 is here.

Carnival of Space #148 is now up at the Celestial Spider. There's a little night music, dirty snowballs in April, nuclear fusion rockets, measuring atmospheres on other planets and gorgeous baby stars. Spin out a thread and drift on over.

Aurora Udate (from Monday 5 April)

Image of aurora from Monday's geomagnetic storm taken by Tony Travaglia of Otago, New Zealand (click to embiggen).

Just updating the aurora alert from Monday. Most parts of Australia were clouded out, correspondent Wes Black saw nothing from Footscray, Melbourne. Andrew Hudspeth was camping at the Walls of Jerusalem in Tasmania and saw a weak auroral display at 9:00 pm. Tony Travalgila in New Zealand got the best view though.

This was the first proper southern aurora (except for those in Antarctica) in a long time. Things can only get better for southern aurora watchers.

Virtual Telescope - Watching TrES-3's exoplanet

I've just had another Virtual Telescope experience, this one at a more reasonable hour. The Virtual Telescope had a world first, a live webcast of an exoplanet transiting its star. The exoplanet being TrES-3b. (click on any image to embiggen)

Located ( from our point of view anyway) in Hercules (see second image) TrES-3 is a world that is nearly twice the size of Jupiter orbiting its sun in just 31 hours (see first image for a Celestia simulation). It will probably crash into its sun in the "near" future.

The lefthand image shows TrES-3, the parent sun of TrES-3b in the CCD window of the virtual telescope (its the one to the left of the blue bar). The righthand image shows the growing light curve as the transit went on. It was pretty exciting to watch a real-time exoplanet transit, listening to Gianluca Masi's narration..The lefthand image is the completed graph of the transit, showing the full dip of the stars light as the exoplanet passed in front of it, and the last image is my participation certificate.